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Last night, I left my computer running overnight with two tabs open in Firefox. When I came back in the morning, the computer had a black screen that said "Disk Boot Failure - Insert System Disk and press Enter. I know it wasn't a power outage because my sons computer was on all night as well. I rebooted the computer after I saw this message and the PC booted into Windows XP just as it normally would. I ran Firefox and it told me it would restore the two tabs that had been left open before the crash.

Could somebody please help me determine what happened here, and if there is anything wrong with my computer, hard disk drive, or other hardware?

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Hard to tell what may have caused the computer to restart, the Event Log is always a good place to start. I suggest running a health and error check on the hard disk drive, HD Tune is free (and portable).

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Disable Quick Scan.

Sometimes this error occurs when you start a computer with a non-bootable USB drive connected (depending on the BIOS settings).

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+1 for suggesting checking the log. – CarlF Jan 12 '10 at 2:19

Quality of power supplies vary greatly per brand/model. Your PC could shut down on a power fluctuation while the other PC powered on the same circuit whould not (if power supplies are of different brand/model and thus quality).

As for the error it's a "scary" error. Whant exactly caused that can't really tell at 100% but I would scan the HDD for bad sectors to be 100% sure there is no damage on HDD.

As Molly pointed out, HD Tune will do the job, as many other out there (and even bundled with the OS.

I would also add that make sure S.M.A.R.T. is enables for all HDDs in your BIOS.

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Could have been a power brown-out. Depending on your house wiring and ages of PSUs in your PC and your son's PC, a fluctuation could have caused your PC to restart but not your son's.

It's unlikely such fluctuations would last long enough to also confuse the disk controller during the boot (leading to the Disk Boot Failure message), but possible.

Regardless of the cause, the shutdown followed by that error implies it's not a software problem.

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